Improvement in bolt-threading machines



UNITED STATES PATENT OFFICE IMPROVEMENT INMBOLT-THREADING MACHINES.

Specification forming part of Lett-ers Patent No. 126,802, dated May 14, 1872.

Specification describing an Improvement in ScreW-CnttingMachines, the invention of JOHN J. GRANT, of Greenfield, in the county of Frank 'lin and State of Massachusetts.

This invention consists in a circularly adjustable head-stock having a number of independent die-holders arranged around its axis or center, and capable of being independently revolved by adjustment of the head-stock,'so as to bring any one of the dieholders, by gears with which they are provided, in connection with a gear-Wheel or pinion on a driving-Shaft common to each of the die-holders, in succes- Siou, or as required. By this combination of devices, increased facility is afforded for cutting different pitches or sizes ot screw-threads in the same machine Without removing the dies from the head-stock. g

In the accompanying drawing which forms part of this specification, Figure l represents a front View of a head-stock with a number of dies for doing different kinds or sizes of work fitted thereto in accordance With the invention. Fig. 2 is a section at the line w m in Fig. 3, which latter View is a section at the line y y in Figs. l and 2.

A is the head-stock of a screw-cutting ma c, of a xed support, Gr. Arranged around the axis orcenter of the adjustable head-stock A, at any suitable but equal distances from its center, area number of independent die-hold ers, B B, made capable of rotation Within or through the head-stock, and the axes of which are parallel With the axis of the head-stock These several die-holders are or may be constructed' to cut different kinds or sizes of screws,

and any one of them is rotated, as required, to cut a particular sized or kind of screw, by adjusting or turning the head-stock A, so as to bring said die in line with the holder that feeds the rod or pin to be screwed to the die, which holder should be arranged to occupy a lateral' position relatively to the head-stock, so as to bring it in line With the driven die. The dieholders B B are independently revolved, as required, by means ot' gears C G on their backs, arranged to mesh with a drivin g-gear or pinion, D, on a shaft, E, common to all the die-holders, accordingly as thehead-stock is turned or adjusted to bring any particular die in drivingconnection with said shaft. The stud or beara number of independent revolving die-holders, B B, having gears G C, in combination with the drivinggear or pinion D, common to each of the die-holders in succession, or as required, substantially as specified.

JOHN J. GRANT.

Witnesses:

FRED. HAYNES, FEED. TUSCH. 

